When you've been a sexy teen idol, a tough action star, danced with Diana, Princess of Wales and been nominated for two Oscars, you think long and hard when someone asks you to put on a dress and portray an outsized, overly protective mother.

John Travolta thought for 14 months before saying "Yes."

The decision was a good one, because he makes a sweet, lovable Edna Turnblad, who sings, dances and is madly in love with her husband, played by Travolta's old pal and fellow former Broadway hoofer Christopher Walken, in the third incarnation of John Waters's musical, Hairspray.

The story, as most people know by now, is set in Baltimore during the 1960s TV dance craze and centres on Edna and Wilbur Turnblad and their daughter Tracy (played by screen newcomer Nikki Blonsky), who graduates from outsider to celebrity trendsetter while kicking down racial barriers on local television.

Edna was portrayed in the original 1988 movie by the transvestite Divine and in the subsequent Broadway show by Harvey Feirstein.

But in this version, which the film's producers Craig Zadan and Neil Meron describe as a "re-invention" based on the stage musical, the first choice for the role was always Travolta. They had originally chosen him for the Billy Flynn role in Chicago, but it went to Richard Gere after Travolta turned it down.

"When they asked me to be Edna Turnblad I said, 'Gee, 32 years as a leading man… why me? What makes you think I'd be the perfect woman?'

"It took me a year and two months to decide to do it. It was a long and arduous decision."

He was finally convinced by director-choreographer Adam Shankman's vision and passion.

"He basically said to me, 'I take this movie personally and if it doesn't come out right, I'm going to die.' And I said, 'Whoa, I've got to go with that guy,' because musicals don't work unless every throttle's on full, so when I got the sense everybody cared, then I said, OK.

"I had the biggest musical in history, Grease, and I wanted to leave it like that, so excuse the pun but it took a lot of grease to get me back in the frying pan."

He was so determined to create the Edna he wanted that he rejected several versions of the fat suit designed for him until he was given one he considered made her suitably curvaceous and voluptuous.

"It wasn't real to me to make her like a refrigerator," he says. "I said, 'Make her as big as you want as long as you give her a waist and make her pretty because it will be more interesting, more appealing and more entertaining.' I wanted people to enjoy looking at her, because if she's grotesque, it's not fun.

"My challenge was making sure I was convincing as a woman, so I drew on a library of memories of watching great female performances in the theatre and on film and in my family, and I used role models like Sophia Loren, Anita Ekberg, Elizabeth Taylor… these women with voluptuous shapes."

He had to spend up to five hours a day encased in a full body suit weighing more than 30lb with five separate gel-filled silicone prosthetic appliances for parts of Edna's face. But it had its compensations.

"I'm happy to be a man, but I miss being groped," he says, laughing. "Everybody tried to grope me all day. Suddenly having breasts and a big bottom gained me so much attention. Men and women wanted to feel my breasts and feel my bum. I must be a slut because I didn't care. Men were flirting with me and I was being given power I never had before. I found it fascinating. Women have power I didn't know they had."

Hairspray is a testament not only to 53-year-old John Travolta's versatility, but to his ability to defy the rules of Hollywood and continue to thrive.

In a business where the adage "they never come back" is especially true, he returned to Hollywood's A-list after languishing in semi-obscurity for a decade and is now as much in demand as he was when his portrayal of the posturing Italian-American Tony Manero in Saturday Night Fever, one of the signature films of the 1970s, earned him an Oscar nomination and international stardom.

Maybe it is due to his well-reported affiliation to the Church of Scientology, but he gives off the aura of almost unnatural calmness. He is remarkably easy to talk to and has an unexpected quality of being able to laugh at himself.

He and his actress wife Kelly Preston avoid the Hollywood social scene, preferring to remain at home some 100 miles up the coast, with their two children, Jett, 15, and seven-year-old Ella Bleu, who is already a budding actress.

An avid flier since he was 16 years old, Travolta also owns a fly-in/fly-out house in Florida, where he lands his Gulfstream 11 and customised 707 jets on a private runway, taxiing right up to the house.

Although he is all movie star nowadays, Travolta is a man who has paid his showbusiness dues. When he was six years old, he took dancing lessons from Gene Kelly's brother; he made his stage debut when he was 12 in Who Will Save the Plowboy?, dropped out of high school when he was 16 to begin work in summer stock and made his Broadway debut in 1974 in Over Here! with the Andrews Sisters.

But after achieving worldwide fame with Saturday Night Fever (1977) and Grease (1978), he became trapped for nearly 10 years in a series of forgettable flops. He was in danger of becoming one of Hollywood's forgotten men until, in 1985, at a party at the White House, Diana, Princess of Wales asked him to dance and he was once more making headlines around the world.

"That was an amazing moment for her and for me because at that time I was having a dip in my career and no one was very interested in me," he says. "But with Princess Diana I was suddenly the only thing that mattered in America to her and I was reborn. I was like, 'Wow! I matter to someone again.' "

Then Quentin Tarantino and Pulp Fiction (1994) restored his acting credibility and won him his second Oscar nomination. Since then, he has thrived in films such as Get Shorty (1995), Broken Arrow (1996), Michael (1996), Face/Off (1997), Primary Colors (1998) and Swordfish (2001), while emerging unscathed from such critically assailed flops as Battlefield Earth (2000).

His most recent film, Wild Hogs (2007), was a huge financial success, and he is due to start work soon on the Walt Disney film Old Dogs, which co-stars his wife and daughter. He is also awaiting a final script for Dallas, the movie version of the 1970s television series in which he is due to play JR.

"As you get older you have to force yourself to have new dreams," he says. "For instance, I've been flying for 37 years but now teaching others to fly is interesting for me. Sometimes you have to find new angles on life to keep you interested, like sharing successes and inspiring and helping others. You have to go out of your way to activate your dreams and keep them going in this third chapter of your life."

CROSS-DRESSING AT THE MOVIES

Some Like It Hot (1959)

The absolute mother of cross-dressing comedies, Billy Wilder's movie remains a thing of beauty - not, perhaps, something that could be said of the suspiciously big-boned Daphne and Josephine.

Mrs Doubtfire (1993)

Robin Williams is like a kiddy in a sweetshop as the husband who, after an acrimonious divorce, decides to pretened to be Euphegenia Doubtfire, nanny extraordinary, in order to spend more time with his children.

It all requires mammoth suspension of disbelief, but there's a nicely waspish edge to the script and much of it is far funnier than it has any right to be.

Kind Hearts and Coronets (1949)

Alec Guinness plays pursed-lipped Suffragette Lady Agatha, the fourth of eight members of the D'Ascoyne family (all played by Guinness) murdered by Dennis Price in pursuit of the dukedom he believes should be his.

"I shot an arrow in the air/She fell to earth in Berkeley Square," he says gaily after downing her hot-air balloon.

Tootsie (1982)

Dustin Hoffman's portrayal of a struggling young actor who turns himself into a middle-aged woman to get a part - and thereby gains an unwelcome insight into life on the other side of the sexual divide - won him an Oscar nomination. His biggest problem with the role? Getting the voice right, he said.

The Crying Game (1992)

If you've never seen this film, stop reading now, because the revelation that the sexy, sultry Dil (Jaye Davidson) is actually a boy is the plot's big twist, helping to make this one of Neil Jordan's biggest hits. Much confusion among male viewers who found themselves fancying her/him.